Harbouring Aliens: Ports as Habitats for Non-native Species

Abstract

Non-native species are widely regarded as a significant environmental threat and have been associated with biodiversity loss, species extinctions and the altering of ecosystem services. Shipping is the largest transport vector for aquatic species worldwide and ports, being central to this industry, are considered potential ‘hotspots’ for non-native species introductions. Ports are often heavily industrialised areas which can hinder access and the use of standard survey methods. As such, our knowledge of non-native species within UK ports is poor. As the foundation for this research I developed two different settlement surveys designed specifically to overcome some of the obstacles associated with working within active port environments. Surveys were deployed across five ports in South Wales, UK. I detected 13 non-native species and described the wider fouling communities present within each studied port. Whole community structure and their succession varied highly between ports, with salinity being the primary driver of differences between port communities. Significant differences in the observed non-native species between ports, independent of geographic proximity, highlighted the need to monitor individual ports with a view to implementing bespoke, effective management strategies. Colonisation of different material substrates was quantified and revealed that whilst the community structure varied between material types, non-native species would readily colonise all studied materials. These findings have particular importance for the management of non-native species within ports and have been used to inform port biosecurity procedures within the studied region. The successful deployment of the tailored survey methods within active ports will encourage regular monitoring for non-native species within UK ports. This research also showed that collaborations between researchers and port authorities can be highly effective for both parties and may indeed be necessary if we are to successfully manage aquatic non-native species within the UK.